compositor-worker: cc->blink mutation plumbing

content/renderer/gpu/render_widget_compositor.h

Index: content/renderer/gpu/render_widget_compositor.h
diff --git a/content/renderer/gpu/render_widget_compositor.h b/content/renderer/gpu/render_widget_compositor.h
index 9600506a5e0fbf8967d503e0b72b40e5fd4927a2..215d31db386f7003040c67cd1d38b601693c5887 100644
--- a/content/renderer/gpu/render_widget_compositor.h
+++ b/content/renderer/gpu/render_widget_compositor.h
@@ -158,6 +158,7 @@ class CONTENT_EXPORT RenderWidgetCompositor
                            const gfx::Vector2dF& elastic_overscroll_delta,
                            float page_scale,
                            float top_controls_delta) override;
+  void ApplyMutations(const cc::LayerTreeMutations& mutations) override;
   void RequestNewOutputSurface() override;
   void DidInitializeOutputSurface() override;
   void DidFailToInitializeOutputSurface() override;